Abstract
The high cost of reducing complex polysaccharides to fermentable sugars from biomass remains the main obstacle for the large-scale production of cellulosic ethanol. The cost of cellulases and hemicellulases contribute substantially to the price of ethanol and, therefore, further studies aimed at understanding and improving the efficiency and stability of these enzymes are of fundamental importance. The filamentous fungus Aspergillus niger is a major producer of such proteins, and their expression is regulated by transcription factors XlnR and CreA. A detailed study may allow the design of modified forms of these transcription factors leading to constitutive expression or independent of inducer / repressor, enabling higher production of enzymes for lignocellulosic biomass processing. Another important way to boost the production of bioethanol is the improvement of enzymes, which are involved in the process of cell wall degradation. Therefore, we also propose to study proteins whose level is regulated by the transcription factors, XlnR and CreA. The accumulation of knowledge, mainly in biophysical and structural aspects, will aid to rationally modify these enzymes in order to make them more stable and highly active under conditions imposed by industrial processes. Expansins are proteins from plants without hydrolytic activity that promotes the breakdown of the crystallinity of cellulose microfibrils. The swollenins, a group of expansins, have been shown to be important for efficient saccharification of the cell wall and therefore they were also included in this project. The structural studies of these proteins will be used for comparisons with the expansins, which have similar activity but different structural organization and can contribute to determine their mode of action. Thus, synergistically, we hope to provide structural data at molecular level which can help to elucidate the molecular mechanisms involving gene regulation of hydrolytic enzymes as well as from their genes that have key role in the degradatation of lignocellulosic biomass. It could enable new strategies for economically viable production of second-generation bioethanol from the material currently considered a waste by bioethanol industry. (AU)
Scientific publications
(9)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
SANTOS, CAMILA RAMOS;
HOFFMAM, ZAIRA BRUNA;
DE MATOS MARTINS, VANESA PEIXOTO;
ZANPHORLIN, LETICIA MARIA;
DE PAULA ASSIS, LEANDRO HENRIQUE;
HONORATO, RODRIGO VARGAS;
LOPES DE OLIVEIRA, PAULO SERGIO;
RULLER, ROBERTO;
MURAKAMI, MARIO TYAGO.
Molecular Mechanisms Associated with Xylan Degradation by Xanthomonas Plant Pathogens.
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NOV 14 2014.
Web of Science Citations: 20.
SANTOS, CAMILA R.;
POLO, CARLA C.;
COSTA, MARIA C. M. F.;
NASCIMENTO, ANDREY F. Z.;
MEZA, ANDREIA N.;
COTA, JUNIO;
HOFFMAM, ZAIRA B.;
HONORATO, RODRIGO V.;
OLIVEIRA, PAULO S. L.;
GOLDMAN, GUSTAVO H.;
GILBERT, HARRY J.;
PRADE, ROLF A.;
RULLER, ROBERTO;
SQUINA, FABIO M.;
WONG, DOMINIC W. S.;
MURAKAMI, MARIO T.
Mechanistic Strategies for Catalysis Adopted by Evolutionary Distinct Family 43 Arabinanases.
Journal of Biological Chemistry,
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MAR 14 2014.
Web of Science Citations: 13.
HOFFMAM, ZAIRA B.;
OLIVEIRA, LEANDRO C.;
COTA, JUNIO;
ALVAREZ, THABATA M.;
DIOGO, JOS A.;
NETO, MARIO DE OLIVEIRA;
CITADINI, ANA PAULA S.;
LEITE, VITOR B. P.;
SQUINA, FABIO M.;
MURAKAMI, MARIO T.;
RULLER, ROBERTO.
Characterization of a Hexameric Exo-Acting GH51 alpha-l-Arabinofuranosidase from the Mesophilic Bacillus subtilis.
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v. 55,
n. 3,
p. 260-267,
NOV 2013.
Web of Science Citations: 6.
SANTOS, CAMILA RAMOS;
POLO, CARLA CRISTINA;
CORREA, JULIANA MOCO;
GARCIA SIMAO, RITA DE CASSIA;
VICENTE SEIXAS, FLAVIO AUGUSTO;
MURAKAMI, MARIO TYAGO.
The accessory domain changes the accessibility and molecular topography of the catalytic interface in monomeric GH39 ss-xylosidases.
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OCT 2012.
Web of Science Citations: 11.
DOS SANTOS, CAMILA RAMOS;
PAIVA, JOICE HELENA;
MEZA, ANDREIA NAVARRO;
COTA, JUNIO;
ALVAREZ, THABATA MARIA;
RULLER, ROBERTO;
PRADE, ROLF ALEXANDER;
SQUINA, FABIO MARCIO;
MURAKAMI, MARIO TYAGO.
Molecular insights into substrate specificity and thermal stability of a bacterial GH5-CBM27 endo-1,4-beta-D-mannanase.
Journal of Structural Biology,
v. 177,
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p. 469-476,
FEB 2012.
Web of Science Citations: 18.
SANTOS, CAMILA R.;
PAIVA, JOICE H.;
SFORCA, MAURICIO L.;
NEVES, JORGE L.;
NAVARRO, RODRIGO Z.;
COTA, JUNIO;
AKAO, PATRICIA K.;
HOFFMAM, ZAIRA B.;
MEZA, ANDREIA N.;
SMETANA, JULIANA H.;
NOGUEIRA, MARIA L.;
POLIKARPOV, IGOR;
XAVIER-NETO, JOSE;
SQUINA, FABIO M.;
WARD, RICHARD J.;
RULLER, ROBERTO;
ZERI, ANA C.;
MURAKAMI, MARIO T.
Dissecting structure-function-stability relationships of a thermostable GH5-CBM3 cellulase from Bacillus subtilis 168.
Biochemical Journal,
v. 441,
n. 1,
p. 95-104,
JAN 1 2012.
Web of Science Citations: 49.
FURTADO, GILVAN PESSOA;
RIBEIRO, LUCAS FERREIRA;
SANTOS, CAMILA RAMOS;
TONOLI, CELISA CALDANA;
DE SOUZA, ANGELICA RODRIGUES;
OLIVEIRA, RENATA ROCHA;
MURAKAMI, MARIO TYAGO;
WARD, RICHARD JOHN.
Biochemical and structural characterization of a beta-1,3-1,4-glucanase from Bacillus subtilis 168.
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v. 46,
n. 5,
p. 1202-1206,
MAY 2011.
Web of Science Citations: 29.